A tetrairidium cluster with a bridging SO 2: The synthesis, fluxional behaviour, and crystal structure of Ir 4(CO) 9(μ 2-CO) 2(μ 2-SO 2)

Abstract

The reaction of SO 2 with Ir 4(CO) 11(norborn-2-ene) yields Ir 4(CO) 9(μ 2-CO) 2(μ 2-SO 2) (i). X-ray diffraction shows that I contains a sulphur dioxide ligand and two CO groups, all three bridging between two basal metal atoms. The lowest-energy CO scrambling process for I has been determined by 13C NMR studies. The thermal stability and high solubility of I (compared to Ir 4(CO) 12) make it a good starting material for the synthesis of other tetrairidium clusters.